From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH] Add user defined tag calculation callback to librte_distributor. Date: Thu, 06 Nov 2014 11:36:09 +0100 Message-ID: <9190772.1rnKUO3oNV@xps13> References: <1415194237-1219-1-git-send-email-jigsaw@gmail.com> <20141106092228.GA3056@bricha3-MOBL3> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev-VfR2kkLFssw@public.gmane.org, jigsaw To: Bruce Richardson Return-path: In-Reply-To: <20141106092228.GA3056@bricha3-MOBL3> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" 2014-11-06 09:22, Bruce Richardson: > On Wed, Nov 05, 2014 at 07:24:13PM +0200, jigsaw wrote: > > http://dpdk.org/browse/dpdk/tree/lib/librte_distributor/rte_distributor.c#n285 > > > > new_tag = (next_mb->hash.rss | 1); > > > > Why the logical OR is needed? > > That's needed to ensure that we never track a tag with an actual value of zero. > We instead always force the low bit to be 1, so that we can use zero as an > "empty" value. Bruce, could you check how this code may be better commented please? This discussion shows that the distributor library probably needs more explanations in the code or doxygen. Thanks -- Thomas